# Solar Panel Calculator Plus vs Mariner's Draft Survey

The clearest difference is price: Mariner's Draft Survey at Free against Solar Panel Calculator Plus's $2.99. Mariner's Draft Survey also leads on update cadence (every 4 days vs every 47 months). Solar Panel Calculator Plus's advantage is iOS requirement (12.0 vs 15.5). On ads, in-app purchases and device support there is nothing between them.

Mariner's Draft Survey is free to download; Solar Panel Calculator Plus costs $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Solar Panel Calculator Plus ships an update every 47 months, Mariner's Draft Survey every 4 days. The most recent releases landed on November 2, 2026 and October 31, 2026 respectively.

## The numbers

| Metric | Solar Panel Calculator Plus | Mariner's Draft Survey |
| --- | --- | --- |
| Price | $2.99 | **Free** |
| Rating | **[3.3 (23 ratings)](https://appshunter.io/ios/app/solar-panel-calculator-plus/id1358184660/reviews)** | — |
| Number of ratings | **23** | — |
| Positive reviews | 25.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 47 months | **Every 4 days** |
| Monetization | Paid | — |
| Size | 8 MB | 75 MB |
| Requires iOS | **12.0** | 15.5 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Nitrio](https://appshunter.io/developer/321121189) | [Burak Yesilirmak](https://appshunter.io/developer/6817890583) |

## What reviewers say

### Solar Panel Calculator Plus

[App page](https://appshunter.io/ios/app/solar-panel-calculator-plus/id1358184660)

Calculate custom off-grid solar home power systems. Determine the exact number of solar panels and battery capacity needed for your energy usage. Helps plan system size, inverter requirements, and battery bank specifications.

**Highlights:** Calculate solar panel requirements, Determine battery capacity, Calculate inverter size, Estimate daily energy usage, Plan days of autonomy, Optimize battery life calculations

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### Mariner's Draft Survey

[App page](https://appshunter.io/ios/app/mariners-draft-survey/id6818049235)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Solar Panel Calculator Plus free?

Solar Panel Calculator Plus costs $2.99, with no in-app purchases.

### Is Mariner's Draft Survey free?

Mariner's Draft Survey is free to download, with no in-app purchases.

### Do Solar Panel Calculator Plus or Mariner's Draft Survey have ads?

Neither Solar Panel Calculator Plus nor Mariner's Draft Survey shows ads.

### Which is updated more often, Solar Panel Calculator Plus or Mariner's Draft Survey?

Solar Panel Calculator Plus ships an update every 47 months, and Mariner's Draft Survey every 4 days. Most recently, Solar Panel Calculator Plus was updated on November 2, 2026 and Mariner's Draft Survey on October 31, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*